This invention generally relates to an eye testing device by which the individual being tested is asked to identify certain characters of an eye test pattern, and more particularly to a device by which selected characters or portions of the eye test pattern within the device are readily, accurately and clearly designated by means of structure that is located outside of the enclosed casing of the device.
Compact eye testing devices are well-known for use in conducting limited testing of opthalmic abilities of individuals. Such devices are particularly well suited for administering drivers license vision tests and for quickly checking the vision of large numbers of students, including relatively young students. Devices of this type are of a general character such as described in U.S. Pat. No. 3,012,472. In such devices, a vision test pattern is located within an enclosed casing, which casing has means for illuminating and viewing the test pattern. The actual vision testing is accomplished by asking the individual being tested to identify certain characters, typically a line of alphabet letters.
A common difficulty that is often encountered by the operator conducting vision tests on these types of devices is with respect to the means by which the operator must indicate to the individual being tested exactly which character or characters the operator is requesting to be identified by the person being tested. Typically, in devices of this type, the person administering the vision test inserts an elongated pointer into the device through an opening in the wall thereof and asks the person being tested to identify the characters designated by the pointer. Usually, the test administrator will first point to characters of the largest type size on the test pattern and gradually indicate characters of smaller type size until the characters are no longer legible to the person being tested.
A principle difficulty of this direct pointing approach is that the pointer or other indicator means often obscures the characters being indicated and/or does not precisely designate the desired characters, leading to confusion and error, especially when the individual being tested is a young child. Another related difficulty that is often evident while using such devices is caused by the fact that the test pattern is not readily visible or directly visible by the operator who must look through an opening in the side of the device, which is both difficult and fatiguing. This, too, can lead to error and an inaccurate vision test.
These difficulties are solved by the present invention by modifying these types of devices to include a duplicate test pattern on a stage that is exterior to the device within which the interior illuminated test pattern is located. Provided in association with the stage and the interior test pattern, is masking means for simultaneous designation of identical characters on both the interior and the exterior test patterns, which designation is accomplished through manipulation of the mask of the operator, which manipulation takes place on the external stage.
It is accordingly a general object of this invention to provide an improved eye testing device.
Another object of the present invention is an improved eye testing method and device by which the characters to be identified by the person being tested are designated without the use of a pointer or the like.
Another object of the present invention is an improved vision testing device and method that includes means for remotely designating test characters in a precise and accurate manner.